JPH0574799B2 - - Google Patents
Info
- Publication number
- JPH0574799B2 JPH0574799B2 JP59106083A JP10608384A JPH0574799B2 JP H0574799 B2 JPH0574799 B2 JP H0574799B2 JP 59106083 A JP59106083 A JP 59106083A JP 10608384 A JP10608384 A JP 10608384A JP H0574799 B2 JPH0574799 B2 JP H0574799B2
- Authority
- JP
- Japan
- Prior art keywords
- electrolytic
- decontamination
- electrolytic solution
- tank
- solution
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000005202 decontamination Methods 0.000 claims description 56
- 230000003588 decontaminative effect Effects 0.000 claims description 54
- 239000008151 electrolyte solution Substances 0.000 claims description 47
- 229910052751 metal Inorganic materials 0.000 claims description 42
- 239000002184 metal Substances 0.000 claims description 42
- 238000003756 stirring Methods 0.000 claims description 26
- 239000003792 electrolyte Substances 0.000 claims description 24
- 239000007789 gas Substances 0.000 claims description 14
- 150000002739 metals Chemical class 0.000 claims description 11
- 239000000243 solution Substances 0.000 claims description 11
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 8
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 claims description 7
- 229910001882 dioxygen Inorganic materials 0.000 claims description 7
- 229910017604 nitric acid Inorganic materials 0.000 claims description 6
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 5
- 239000012535 impurity Substances 0.000 claims description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 4
- 239000007788 liquid Substances 0.000 claims description 3
- 238000006243 chemical reaction Methods 0.000 description 13
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 12
- 238000005868 electrolysis reaction Methods 0.000 description 12
- 230000002285 radioactive effect Effects 0.000 description 9
- 239000010814 metallic waste Substances 0.000 description 7
- 238000011109 contamination Methods 0.000 description 6
- 229910052742 iron Inorganic materials 0.000 description 6
- 239000003595 mist Substances 0.000 description 6
- 230000000694 effects Effects 0.000 description 5
- 239000002699 waste material Substances 0.000 description 5
- 238000005253 cladding Methods 0.000 description 4
- 239000002440 industrial waste Substances 0.000 description 4
- 238000009390 chemical decontamination Methods 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000004090 dissolution Methods 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 238000007689 inspection Methods 0.000 description 3
- 238000012423 maintenance Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 239000001257 hydrogen Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 238000010248 power generation Methods 0.000 description 2
- 230000001737 promoting effect Effects 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 239000004927 clay Substances 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 230000005251 gamma ray Effects 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 239000010410 layer Substances 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- 239000012466 permeate Substances 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 238000003918 potentiometric titration Methods 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 239000002901 radioactive waste Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- 239000002912 waste gas Substances 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Landscapes
- Electrolytic Production Of Metals (AREA)
Description
【発明の詳細な説明】
［発明の技術分野］
本発明は、原子力発電設備等で発生する被処理
金属としての放射性金属廃棄物を除染するための
放射能で汚染された金属の除染装置に関する。[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a decontamination device for metals contaminated with radioactivity for decontaminating radioactive metal waste as metals to be treated generated in nuclear power generation facilities, etc. Regarding.
［発明の技術的背景とその問題点］
一般に原子力発電所等で発生する放射性金属廃
棄物は、原子力発電所内に永久貯蔵され、環境に
悪影響を与えないようにしている。[Technical background of the invention and its problems] Radioactive metal waste generated at nuclear power plants and the like is generally stored permanently within the nuclear power plant to prevent it from having a negative impact on the environment.
しかし、このように永久貯蔵すると放射性金属
廃棄物の貯蔵量は増加の一途をたどり、貯蔵スペ
ースの確保が困難になる。特に原子力発電設備等
の放射能で汚染されている配管等はその寸法が大
きく、また容易に減容処理することができないた
めその廃棄物としての貯蔵が困難である。 However, when stored permanently in this way, the amount of radioactive metal waste stored continues to increase, making it difficult to secure storage space. In particular, pipes contaminated with radioactivity from nuclear power generation facilities and the like are large in size and cannot be easily reduced in volume, making it difficult to store them as waste.
このため、放射性金属廃棄物を除染し、その放
射能レベルを自然界における放射能レベル、つま
りバツクグラウンドレベルまで低下させて、一般
の産業廃棄物と同様に取り扱い得るようにするこ
とが検討されている。 For this reason, consideration is being given to decontaminating radioactive metal waste and reducing its radioactivity level to the radioactivity level found in nature, that is, to the background level, so that it can be handled in the same way as general industrial waste. There is.
しかしながら、放射性金属廃棄物はその表面の
材質自体に放射能が浸透しているため、表面に堆
積している放射性クラツドを除去しただけでは完
全な除染はできず、金属自体も溶解して放射能が
浸透した表面層を除去する必要がある。 However, since radioactivity permeates the surface material of radioactive metal waste, complete decontamination is not possible just by removing the radioactive clay deposited on the surface; the metal itself dissolves and releases radiation. It is necessary to remove the surface layer penetrated by the compound.
この放射能除染に際しては、酸等の化学除染剤
を用いる化学除染法や電解除染法が知られてい
る。 For this radioactive decontamination, chemical decontamination methods and electrical decontamination methods using chemical decontamination agents such as acids are known.
前者は形状が複雑な大型機材の被処理材への適
用性は高いものの除染速度が非常に遅く、除染係
数が比較的小さい欠点がある。 Although the former method is highly applicable to large-sized equipment with complex shapes, the decontamination speed is extremely slow and the decontamination coefficient is relatively small.
一方、後者の電解除染法は除染速度、除染係数
は高いものの、逆に形状の複雑な被処理材や大型
機材への適用には問題点がある。 On the other hand, although the latter electric decontamination method has a high decontamination speed and a high decontamination coefficient, it has problems when applied to materials with complex shapes or large equipment.
さらに化学除染装置と電解除染装置で用いる除
染剤は劣化や放射能の蓄積等により、除染不能と
なるため二次廃棄物が増大する問題点があつた。 Furthermore, the decontamination agents used in chemical decontamination equipment and electrolytic decontamination equipment deteriorate and accumulate radioactivity, making decontamination impossible, resulting in an increase in secondary waste.
［発明の目的］
本発明は以上の事情に基づいてなされたもの
で、その目的は放射性金属廃棄物の表面を確実に
溶解でき、従来例の欠点であつた、大型機材や形
状の複雑なものも完全に除染して放射能レベルを
バツクグラウンドレベルまで低下させて、一般の
産業廃棄物と同様に取り扱うことができるまで除
染し、さらに除染剤を再生して二次廃棄物の発生
量を最少に抑えることができる放射能で汚染され
た金属の除染装置を提供することにある。[Object of the invention] The present invention was made based on the above circumstances, and its purpose is to be able to reliably dissolve the surface of radioactive metal waste, and to solve the problems of large equipment and complex-shaped equipment, which were the drawbacks of conventional examples. The waste is completely decontaminated to reduce the radioactivity level to background levels and can be treated like general industrial waste, and the decontamination agent is recycled to generate secondary waste. An object of the present invention is to provide a decontamination device for metals contaminated with radioactivity, which can minimize the amount of radioactivity.
［発明の概要］
すなわち本発明は、Ce3+−Ce4+−HNO3溶液
系の電解液を収容し放射能で汚染された被処理金
属が液中に浸漬される電解槽と、この電解槽内の
電解液中に設けられ直流電源に電源ケーブルを介
して接続される陽極および陰極と、前記電解液を
撹拌する撹拌機構と、電解槽に連接され電解液中
の不純物を回収除去するフイルタと、電解槽内に
発生した硝酸蒸気および水蒸気を回収し水素ガス
および酸素ガスを排気する排ガス処理装置とを具
備することを特徴とする放射能で汚染された金属
の除染装置である。また、本発明は、Ce3+−
Ce4+−HNO3溶液系の電解液を収容する電解槽
と、この電解槽内の電解液中に設けられ直流電源
に電源ケーブルを介して接続される陽極および陰
極と、前記電解液を循環させる循環ラインにより
電解槽に連通され電解液を貯溜して放射能で汚染
された被処理金属が液中に浸漬される除染槽と、
電解槽および除染槽内の少なくとも一方の電解液
を撹拌する撹拌機構と、電解槽および除染槽の少
なくとも一方に連接され電解液中の不純物を回収
除去するフイルタと、電解槽および除染槽内に発
生した硝酸蒸気および水蒸気を回収し水素ガスお
よび酸素ガスを排気する排ガス処理装置とを具備
することを特徴とする放射能で汚染された金属の
除染装置である。[Summary of the Invention] That is, the present invention provides an electrolytic cell containing an electrolytic solution of a Ce 3+ −Ce 4+ −HNO 3 solution system and in which a metal to be treated contaminated with radioactivity is immersed in the electrolytic solution; An anode and a cathode provided in the electrolytic solution in the tank and connected to a DC power supply via a power cable, a stirring mechanism that stirs the electrolytic solution, and a filter that is connected to the electrolytic tank and collects and removes impurities in the electrolytic solution. This decontamination device for metals contaminated with radioactivity is characterized by comprising: a. Further, the present invention provides Ce 3+ −
An electrolytic cell containing an electrolytic solution of Ce 4+ −HNO 3 solution, an anode and a cathode provided in the electrolytic solution in this electrolytic cell and connected to a DC power supply via a power cable, and the electrolytic solution is circulated. a decontamination tank that is connected to the electrolytic tank through a circulation line that stores an electrolytic solution, and in which the radioactively contaminated metal to be treated is immersed;
a stirring mechanism that stirs the electrolyte in at least one of the electrolytic cell and the decontamination tank; a filter connected to at least one of the electrolytic cell and the decontamination tank that collects and removes impurities in the electrolyte; and the electrolytic cell and the decontamination tank. This is a decontamination device for metals contaminated with radioactivity, characterized by comprising an exhaust gas treatment device that recovers nitric acid vapor and water vapor generated within the device and exhausts hydrogen gas and oxygen gas.
本発明によれば、電解液を撹拌することによ
り、Ce（Iv）イオンを効率良く生成および再生す
ることができ、また放射性金属廃棄物の除染速度
を速くすることができる。 According to the present invention, by stirring the electrolytic solution, Ce(Iv) ions can be efficiently generated and regenerated, and the decontamination rate of radioactive metal waste can be increased.
さらにフイルタを設けることにより、クラツド
と不純物が電極へ付着することを防ぐことができ
るため、Ce（Iv）イオンを効率良く再生すること
ができる。そのうえ、電解槽と除染槽とをそれぞ
れ独立に設けることにより、電極等の破損を防ぐ
ことができるため保守点検が容易である。 Furthermore, by providing a filter, it is possible to prevent crud and impurities from adhering to the electrode, so that Ce(Iv) ions can be efficiently regenerated. Moreover, by providing the electrolytic bath and the decontamination bath independently, damage to the electrodes and the like can be prevented, making maintenance and inspection easy.
［発明の実施例］
以下本発明の第１の実施例を第１図を参照しな
がら説明する。[Embodiments of the Invention] A first embodiment of the present invention will be described below with reference to FIG.
第１図において、符号１は電解槽で、この電解
槽１内には電解液２として、Ce3+−Ce4+−
HNO3溶液が収納されている。電解液２の中には
被汚染物である放射能で汚染された被処理金属３
と、陽極４および陰極５が浸漬されている。被処
理金属３は電解槽１の上方に設配された固定機構
６から垂下されたケーブル７により吊設され、陽
極４および陰極５は直流電源８に接続されてい
る。電解槽１には循環ライン９が接続されてお
り、電解液２は循環ポンプ１０によりフイルタ１
１を通つて電解槽１下部から噴出される。 In FIG. 1, reference numeral 1 indicates an electrolytic cell, and in this electrolytic cell 1, as an electrolytic solution 2, Ce 3+ −Ce 4+ −
Contains HNO3 solution. The electrolyte 2 contains a metal 3 to be treated which is contaminated with radioactivity.
The anode 4 and cathode 5 are immersed. The metal to be treated 3 is suspended by a cable 7 hanging from a fixing mechanism 6 disposed above the electrolytic cell 1, and the anode 4 and cathode 5 are connected to a DC power source 8. A circulation line 9 is connected to the electrolytic cell 1, and the electrolyte 2 is passed through a filter 1 by a circulation pump 10.
1 and is ejected from the lower part of the electrolytic cell 1.
一方、電解槽１上部側面には排ガスライン１２
が接続され、電解液２から発生するH2O−HNO3
蒸気およびミストは排ガスラインを通つて、コン
デンサ１３で凝縮され、戻し管１４を通つて電解
槽１に回収される。回収しきれなかつたH2O−
HNO3蒸気およびミストは排気ブロア１５に吸引
されてデミスタ１６へ回収される。また、電解液
２から電気分解によつて発生する水素ガスおよび
酸素ガスは排ガスライン１２より空気で希釈され
て装置外に排出される。符号１７は電解液２の加
熱用ヒータである。 On the other hand, an exhaust gas line 12 is installed on the upper side of the electrolytic cell 1.
is connected, and H 2 O−HNO 3 generated from electrolyte 2
The steam and mist pass through the exhaust gas line, are condensed in a condenser 13, and are collected into the electrolytic cell 1 through a return pipe 14. Unrecovered H 2 O−
HNO 3 vapor and mist are sucked into the exhaust blower 15 and collected into the demister 16 . Further, hydrogen gas and oxygen gas generated from the electrolytic solution 2 by electrolysis are diluted with air through the exhaust gas line 12 and discharged to the outside of the apparatus. Reference numeral 17 is a heater for heating the electrolytic solution 2.
以上の如く構成された本発明に係わる放射能汚
染された金属の除染装置は、まず、所定量のCe
（NO3）3をH2O−HNO3溶液に溶解して調整した
電解液２を電解槽１に収容し、循環ポンプ１０に
より電解液２を循環ライン９を通して電解槽１の
下部から噴出させる。電解液２をヒータ１７によ
り所定温度に加熱しまた排気ブロア１５で電解槽
１内を負圧にする。同時に直流電源８により陽極
４と陰極５の間に電圧を印加して所定の電流密度
の電流を流すと以下に示す反応が起り、Ce3+は
Ce4+に変化する。 The apparatus for decontaminating radioactively contaminated metal according to the present invention configured as described above firstly removes a predetermined amount of Ce.
An electrolytic solution 2 prepared by dissolving (NO 3 ) 3 in a H 2 O-HNO 3 solution is placed in an electrolytic cell 1, and a circulation pump 10 blows out the electrolytic solution 2 from the bottom of the electrolytic cell 1 through a circulation line 9. . The electrolytic solution 2 is heated to a predetermined temperature by the heater 17, and the inside of the electrolytic cell 1 is brought to negative pressure by the exhaust blower 15. At the same time, when a voltage is applied between the anode 4 and the cathode 5 by the DC power supply 8 and a current with a predetermined current density is caused to flow, the following reaction occurs, and Ce 3+
Changes to Ce 4+ .
陽極
Ce3+→Ce4+＋e- ……(1)
20H-→H2O＋（１／２）O2（↑）＋2e- ……(2)
陰極
H+＋e-→（１／２）H2（↑） ……(3)
陽極でのCe4+の生成反応はCe3+が拡散して陽
極表面に到達する速度に依存する。そのため、電
解液を電解槽下部から噴出させて撹拌させると
Ce4+生成反応を促進させる効果がある。 Anode Ce 3+ →Ce 4+ +e - ...(1) 20H - →H 2 O+(1/2)O 2 (↑)+2e - ...(2) Cathode H + +e - →(1/2)H 2 (↑) ...(3) The reaction that produces Ce 4+ at the anode depends on the rate at which Ce 3+ diffuses and reaches the anode surface. Therefore, if the electrolyte is spouted from the bottom of the electrolytic tank and stirred,
It has the effect of promoting the Ce 4+ production reaction.
Ce4+が所定濃度になつたならば固定機構６か
ら垂下されたケーブル７に被処理金属３を吊設
し、電解液２（Ce3+−Ce4+−HNO3溶液）に浸
漬する。ここで被処理金属３の表面では以下に示
す反応が起こりクラツドおよび金属Ｍの表面が溶
解するとともに汚染が除去される。 When Ce 4+ reaches a predetermined concentration, the metal to be treated 3 is suspended from the cable 7 hanging from the fixing mechanism 6 and immersed in the electrolytic solution 2 (Ce 3+ −Ce 4+ −HNO 3 solution). Here, the following reaction occurs on the surface of the metal 3 to be treated, and the cladding and the surface of the metal M are dissolved and contamination is removed.
Ｍ＋Ce4+→M+＋Ce3+ ……(4)
(4)式の反応はCe4+が拡散して金属Ｍの表面３
に到達する速度に依存する。そのため、電解液２
を撹拌させることは溶解反応を促進させる効果が
ある。所定時間浸漬後、被処理金属３はクラツド
および内面の汚染層が除去され、放射能レベル、
いわゆるバツクグラウンドレベルまで低下され、
一般の産業廃棄物と同様に取り扱うことができ
る。 M + Ce 4+ →M + +Ce 3+ ...(4) In the reaction of equation (4), Ce 4+ diffuses to the surface 3 of metal M.
depends on the speed at which it is reached. Therefore, electrolyte 2
Stirring has the effect of promoting the dissolution reaction. After being immersed for a predetermined period of time, the contamination layer on the metal 3's cladding and inner surface is removed, and the radioactivity level is reduced.
reduced to the so-called background level,
It can be handled in the same way as general industrial waste.
一方、被処理金属３と反応して還元された
Ce3+は、常時直流電源８から電圧を印加し、所
定の電流密度の電流を流しているため、(1)式の反
応が起りCe4+を生成する。また、電解液２中に
浮遊する鉄等の酸化物を循環ライン９に設けたフ
イルタ１１で回収するため、陽極４へ鉄等の酸化
物が付着するのを防ぐことができ、効率良く
Ce4+を生成することができる。 On the other hand, it reacts with the metal to be treated 3 and is reduced.
Since a voltage is constantly applied to Ce 3+ from the DC power supply 8 and a current of a predetermined current density is passed through the Ce 3+ , the reaction of formula (1) occurs and Ce 4+ is generated. In addition, since oxides such as iron floating in the electrolytic solution 2 are recovered by the filter 11 installed in the circulation line 9, it is possible to prevent oxides such as iron from adhering to the anode 4, and to improve efficiency.
Can produce Ce 4+ .
一方、電解液２から発生するH2O−HNO3蒸気
およびミストは、電解槽１の上部に接続した排ガ
スライン１２を通つてコンデンサで凝縮され、戻
し管１４を通つて電解槽１で回収される。回収し
きれなかつたH2O−HNO3蒸気およびミストは排
気ブロア１５に吸引されてデミスタ１６に回収さ
れる。また、電解液２から(2)、(3)式に従つて発生
する水素ガスおよび酸素ガスは排ガスライン１２
よりデミスタ１６を経て空気で希釈されて装置外
に排出される。これにより、硝酸蒸気の装置外へ
の漏洩を防止するとともに、水素ガスの滞留によ
る燃焼、爆発の危険を低減して、作業員の作業の
安全性を高めることができる。 On the other hand, H 2 O-HNO 3 vapor and mist generated from the electrolytic solution 2 pass through the exhaust gas line 12 connected to the upper part of the electrolytic cell 1 , are condensed in a condenser, and are collected in the electrolytic cell 1 via a return pipe 14 . Ru. The H 2 O-HNO 3 vapor and mist that cannot be recovered are sucked into the exhaust blower 15 and recovered into the demister 16 . Further, hydrogen gas and oxygen gas generated from the electrolytic solution 2 according to equations (2) and (3) are transferred to the exhaust gas line 12.
The liquid then passes through the demister 16, is diluted with air, and is discharged outside the apparatus. This prevents leakage of nitric acid vapor to the outside of the apparatus, reduces the risk of combustion and explosion due to accumulation of hydrogen gas, and improves work safety for workers.
次に電解液（Ce3+−Ce4+−HNO3溶液）を電
解する電解槽と被処理金属を除染する除染槽とを
それぞれ独立に設けた第２の実施例について第２
図を参照しながら説明する。 Next, a second example will be described in which an electrolytic bath for electrolyzing an electrolytic solution (Ce 3+ -Ce 4+ -HNO 3 solution) and a decontamination bath for decontaminating the metal to be treated are provided independently.
This will be explained with reference to the figures.
第２図において符号１は第１の実施例で説明し
た例とほぼ同様の電解槽で、電解槽１内には電解
液（Ce3+−Ce4+−HNO3溶液）２が収容されて
いる。電解液２中には陽極４および陰極５が浸漬
され、陽極４および陰極５は直流電源８に接続さ
れている。電解槽１にオーバーフロライン１８が
接続され、電解液２がオーバーフロライン１８を
通つて除染槽１９に供給される。除染槽１９には
被処理金属３が浸漬され、被処理金属３は除染槽
３の上方に配設された固定機構６からケーブル７
により吊設される。除染槽１９には電解液２を撹
拌する撹拌ライン２０が接続され、電解液２は撹
拌ポンプ２１により、フイルタ１１を通つて除染
槽１９の下部から噴出される。また、除染槽１９
には循環ライン２２が接続され、除染槽１９の電
解液２は循環ポンプ２３によりフイルタ１１を通
つて電解槽１の下部から噴出される。 In FIG. 2, reference numeral 1 denotes an electrolytic cell almost similar to the example explained in the first embodiment, and the electrolytic cell 1 contains an electrolytic solution (Ce 3+ −Ce 4+ −HNO 3 solution) 2. There is. An anode 4 and a cathode 5 are immersed in the electrolytic solution 2 , and the anode 4 and the cathode 5 are connected to a DC power source 8 . An overflow line 18 is connected to the electrolytic cell 1, and the electrolytic solution 2 is supplied to a decontamination tank 19 through the overflow line 18. The metal to be treated 3 is immersed in the decontamination tank 19, and the metal to be treated 3 is connected to the cable 7 from the fixing mechanism 6 disposed above the decontamination tank 3.
It is suspended by. A stirring line 20 for stirring the electrolytic solution 2 is connected to the decontamination tank 19 , and the electrolytic solution 2 is ejected from the lower part of the decontamination tank 19 through the filter 11 by a stirring pump 21 . In addition, decontamination tank 19
A circulation line 22 is connected to the decontamination tank 19 , and the electrolytic solution 2 in the decontamination tank 19 is ejected from the lower part of the electrolytic tank 1 through the filter 11 by a circulation pump 23 .
一方、電解槽１と除染槽１９の上部には排ガス
ライン１２が接続され、電解液２から発生する
H2O−HNO3蒸気およびミスト並びに電気分解に
よつて発生する水素および酸素ガスは、排ガスラ
イン１２を通つて第１図で説明したコンデンサ１
３とデミスタ１６および排気ブロア１５で処理さ
れる。なお符号１７は電解液加熱用ヒータであ
る。 On the other hand, an exhaust gas line 12 is connected to the upper part of the electrolytic tank 1 and the decontamination tank 19, and the gas generated from the electrolytic solution 2 is
H2O - HNO3 steam and mist as well as hydrogen and oxygen gas generated by electrolysis are passed through the exhaust gas line 12 to the condenser 1 described in FIG.
3, demister 16 and exhaust blower 15. Note that the reference numeral 17 is a heater for heating the electrolytic solution.
以上の如く構成された本発明に係る放射能で汚
染された金属の除染装置では、まず所定量のCe
（NO3）3をH2O−HNO3溶液に溶解し電解液を調
整して電解槽１と除染槽１９に収容し、循環ポン
プ２３により調整した電解液２を循環ライン２２
を通して電解槽１の下部ら噴出させ、オーバーフ
ロライン１８を通して電解槽１と除染槽１９を循
環させる電解液２をヒータ１７により所定温度に
加熱し、排気ブロア１５で電解槽１内と除染槽１
９内を負圧にする。同時に直流電源８により陽極
４と陰極５の間に電圧を印加し、所定の電流密度
の電流を流す。電解液中では第１図に説明した式
(1)、(2)、(3)の反応が起り、Ce4+が生成する。 In the decontamination apparatus for metals contaminated with radioactivity according to the present invention configured as described above, first, a predetermined amount of Ce is removed.
(NO 3 ) 3 is dissolved in a H 2 O-HNO 3 solution to prepare an electrolytic solution, which is stored in the electrolytic tank 1 and the decontamination tank 19, and the adjusted electrolytic solution 2 is sent to the circulation line 22 by the circulation pump 23.
The electrolytic solution 2 is ejected from the lower part of the electrolytic cell 1 through the overflow line 18 and circulated between the electrolytic cell 1 and the decontamination cell 19 through the heater 17 and heated to a predetermined temperature by the exhaust blower 15. Tank 1
Make negative pressure inside 9. At the same time, a voltage is applied between the anode 4 and the cathode 5 by the DC power supply 8, and a current with a predetermined current density is caused to flow. In the electrolyte, the formula explained in Figure 1
Reactions (1), (2), and (3) occur, and Ce 4+ is produced.
第１図と同様に電解液２を電解槽１の下部から
噴出させて撹拌するため、Ce4+の生成反応が効
率良く促進する。Ce4+が所定濃度になつたなら
ば除染槽１９の上部に設けられている固定機構６
から垂下されたケーブル７に被処理金属３を吊設
し、除染槽１９内の電解液２に浸漬する。同時に
撹拌ポンプ２１により電解２を撹拌ライン２０を
通して除染槽１９の下部から噴出させる。 As in FIG. 1, the electrolytic solution 2 is jetted out from the lower part of the electrolytic cell 1 and stirred, so that the Ce 4+ production reaction is efficiently promoted. When Ce 4+ reaches a predetermined concentration, the fixing mechanism 6 installed at the top of the decontamination tank 19
The metal to be treated 3 is suspended from the cable 7 hanging from the metal 3 and immersed in the electrolyte 2 in the decontamination tank 19. At the same time, the stirring pump 21 causes the electrolysis 2 to be ejected from the lower part of the decontamination tank 19 through the stirring line 20.
ここで、被処理金属の表面では第１図で説明し
た式(4)の反応が起り、クラツドおよび金属表面が
溶解するとともに汚染が除去される第１図と同
様、電解液を除染槽１９の下部から噴出させて撹
拌するため溶解反応が促進する。所定時間浸漬
後、被処理金属３はクラツドおよび汚染槽１９の
内面が除去され、放射能レベルが自然界の放射能
レベル、いわゆるバツクグラウンドレベルまで低
下され、一般の産業廃棄物と同様に取り扱うこと
ができる。 Here, the reaction of formula (4) explained in Fig. 1 occurs on the surface of the metal to be treated, and the cladding and metal surface are dissolved and contamination is removed.Similar to Fig. 1, the electrolyte is poured into the decontamination tank 19. The dissolution reaction is accelerated because it is spouted from the bottom and stirred. After being immersed for a predetermined period of time, the metal 3 to be treated has its cladding and the inner surface of the contaminated tank 19 removed, and its radioactivity level is reduced to the natural radioactivity level, the so-called background level, and it can be handled in the same way as general industrial waste. can.
被処理金属３と反応して還元されたCe3+は、
常時直流電源８から電圧を印加し、所定の電流密
度の電流が流しているため第１図に説明した(1)式
の反応が起りCe4+を再生する。しかも除染槽１
９内の電解液２中に浮遊する鉄等の酸化物を撹拌
ライン２０および循環ライン２２に設けたフイル
タ１１で回収するため、電解槽１の陽極４へ鉄等
の酸化物が付着するのを防ぐことができ、効率良
くCe4+を生成することができる。一方、電解槽
１および除染槽１９内の電解液２から発生する
H2O−HNO3蒸気およびミスト並びに電気分解に
よつて発生する水素および酸素ガスは、電解槽１
および除染槽１９の上部に接続した排ガスライン
１２を通つて、第１図の実施例と同様に処理され
る。 Ce 3+ is reduced by reacting with the metal to be treated 3.
Since a voltage is constantly applied from the DC power source 8 and a current with a predetermined current density is flowing, the reaction of formula (1) explained in FIG. 1 occurs and Ce 4+ is regenerated. Moreover, decontamination tank 1
In order to recover oxides such as iron floating in the electrolyte 2 in the electrolyte 9 with the filter 11 provided in the stirring line 20 and the circulation line 22, it is necessary to prevent the oxides such as iron from adhering to the anode 4 of the electrolytic cell 1. can be prevented and Ce 4+ can be efficiently generated. On the other hand, the electrolyte 2 in the electrolytic tank 1 and the decontamination tank 19 generates
H 2 O−HNO 3 steam and mist as well as hydrogen and oxygen gas generated by electrolysis are transferred to the electrolytic cell 1.
The waste gas is then processed in the same manner as in the embodiment shown in FIG. 1 through the exhaust gas line 12 connected to the upper part of the decontamination tank 19.
なお、電極材料はHNOおよびCe4+等の強酸化
剤に耐食性を示し、電解しても研磨されない材
料、例えば白金およびチタン等を用いる。 Note that the electrode material is a material that shows corrosion resistance to strong oxidizing agents such as HNO and Ce 4+ and is not polished even by electrolysis, such as platinum and titanium.
また、電解液の撹拌機能としては、撹拌機等を
用いてもよい。電解液の加熱源としては、外部ヒ
ータに限らず投込式ヒータ等を用いてもよい。 Furthermore, a stirrer or the like may be used to stir the electrolytic solution. As a heating source for the electrolytic solution, not only an external heater but also an immersion type heater or the like may be used.
次に上記実施例の効果を確認するために行なつ
た実験の結果を第３図および第４図によつて説明
する。 Next, the results of experiments conducted to confirm the effects of the above embodiment will be explained with reference to FIGS. 3 and 4.
第３図において線ａは撹拌なしの電解、線ｂは
撹拌ありの電解を示している。なお、縦軸は電解
液中のCe4+濃度および電流効率を、横軸は電解
時間を示している。 In FIG. 3, line a shows electrolysis without stirring, and line b shows electrolysis with stirring. Note that the vertical axis shows the Ce 4+ concentration and current efficiency in the electrolytic solution, and the horizontal axis shows the electrolysis time.
電解条件としては、Ce（NO3）3濃度0.8mol／
、HNO3濃度2mol／の電解液を電解液温度
80℃、電流密度0.3A／cm2で電解してCe4+の生成
を行なつた。Ce4+生成量は電位差滴定法で分析
して求め、電流効率ηは以下のようにして求め
た。 The electrolytic conditions are Ce(NO 3 ) 3 concentration 0.8 mol/
, an electrolyte with a HNO 3 concentration of 2 mol/
Ce 4+ was generated by electrolysis at 80° C. and a current density of 0.3 A/cm 2 . The amount of Ce 4+ produced was determined by analysis using a potentiometric titration method, and the current efficiency η was determined as follows.
η＝（96485×Ce4+生成量（mol／）×電解液
液量（））／（電解時間（SEC）×電流
（Ａ））
第３図から明らかなように、電解液を撹拌して
電解を行なえば効率良くCe4+を生成および再生
することができる。 η=(96485×Ce 4+ production amount (mol/)×electrolyte amount ())/(electrolysis time (SEC)×current (A)) As is clear from Figure 3, the electrolyte was stirred. If electrolysis is performed, Ce 4+ can be efficiently generated and regenerated.
次に第４図について説明する。第３図の結果を
基にCe4+濃度0.6mol／、HNO3濃度2mol／
電解液を80℃に加熱して汚染金属（SUS304、2B
×SCH40×500）を浸漬し、同時に0.3Acm2の電流
密度でCe4+の再生を行なつた。曲線Ｃは電解液
を撹拌しないで被処理金属を浸漬した場合、曲線
ｄは電解液を撹拌して被処理金属を浸漬した場
合、水平線ｅはバツクグランドを示している。な
お、縦軸γ線強度（cpm）を、横軸は除染時間を
示している。 Next, FIG. 4 will be explained. Based on the results in Figure 3, Ce 4+ concentration is 0.6 mol/, HNO 3 concentration is 2 mol/
Heat the electrolyte to 80℃ to remove contaminated metals (SUS304, 2B
× SCH40 × 500) was immersed in the solution, and Ce 4+ was simultaneously regenerated at a current density of 0.3 Acm 2 . Curve C shows the case where the metal to be processed is immersed without stirring the electrolyte, curve d shows the case where the metal to be processed is immersed with the electrolyte being stirred, and the horizontal line e shows the background. Note that the vertical axis represents gamma ray intensity (cpm), and the horizontal axis represents decontamination time.
第４図から明らかなように電解液を撹拌して被
処理金属を浸漬すれば、除染時間60分間で表面の
汚染量をバツクグラウンドレベルまで低下させる
ことができ、電解液を撹拌せずに、被処理金属を
浸漬した場合は120分除染しても表面の汚染量を
バツクグラウンドレベルまで低下させることが認
められなかつた。 As is clear from Figure 4, if the electrolyte is stirred and the metal to be treated is immersed, the amount of contamination on the surface can be reduced to the background level within 60 minutes of decontamination, without stirring the electrolyte. When the metal to be treated was immersed, it was not observed that the amount of surface contamination could be reduced to the background level even after 120 minutes of decontamination.
また、電解液中に浮遊する鉄等の酸化物をフイ
ルタで回収するため、陽極へ酸化物が付着するの
を防ぐことができ、さらに効率良くCe4+の再生
ができる。 In addition, since oxides such as iron floating in the electrolyte are collected by a filter, it is possible to prevent the oxides from adhering to the anode and regenerate Ce 4+ more efficiently.
さらに電解槽と除染槽をそれぞれ独立に設ける
ことにより被処理金属が電極に衝突し破損するこ
とを防ぐことができ、しかも被処理金属の出し入
れが簡単であるため、機器の保守点検が容易にな
る。 Furthermore, by providing an electrolytic tank and a decontamination tank independently, it is possible to prevent the metal to be processed from colliding with the electrodes and damaging them, and since it is easy to take in and out the metal to be processed, maintenance and inspection of the equipment is easy. Become.
［発明の効果］
上記の如く、本発明によれば、電解液を撹拌す
ることにより、効率良くCe4+の生成と再生を行
なうことができ、しかも鉄等の酸化物をフイルタ
で捕集すれば、さらに効率良くCe4+の再生がで
きる。[Effects of the Invention] As described above, according to the present invention, Ce 4+ can be efficiently generated and regenerated by stirring the electrolytic solution, and oxides such as iron can be collected with a filter. If so, Ce 4+ can be regenerated even more efficiently.
また、電解液の撹拌により被処理金属の表面の
溶解反応を促進させ、放射性廃棄物の放射能レベ
ルをバツクグラウンドレベルまで低下させること
ができ、一般の廃棄物と同様に取り扱うことがで
きる等その効果は顕著なものがある。そのうえ電
解槽と除染槽をそれぞれ独立に設けることにより
機器の保守点検が容易になる。 In addition, by stirring the electrolytic solution, the dissolution reaction on the surface of the metal to be treated can be promoted, reducing the radioactivity level of radioactive waste to the background level, allowing it to be handled in the same way as general waste, etc. The effects are remarkable. Furthermore, by providing an electrolytic tank and a decontamination tank independently, maintenance and inspection of the equipment becomes easier.
第１図および第２図は本発明の各々の実施例を
示す系統図、第３図は本発明と従来例による電解
時間とCe4+の濃度の関係を示す特性図、第４図
は本発明と従来例による除染時間と表面汚染量の
低減との関係を示す特性図である。
１……電解槽、２……電解液、３……被処理金
属、４……陽極、５……陰極、８……直流電源、
９……循環ライン、１１…フイルタ、１９……除
染槽、２０……撹拌ライン、２１……撹拌ポン
プ。
FIGS. 1 and 2 are system diagrams showing each embodiment of the present invention, FIG. 3 is a characteristic diagram showing the relationship between electrolysis time and Ce 4+ concentration according to the present invention and the conventional example, and FIG. FIG. 3 is a characteristic diagram showing the relationship between decontamination time and reduction in surface contamination amount according to the invention and a conventional example. 1... Electrolytic cell, 2... Electrolyte, 3... Metal to be treated, 4... Anode, 5... Cathode, 8... DC power supply,
9... Circulation line, 11... Filter, 19... Decontamination tank, 20... Stirring line, 21... Stirring pump.
Claims (1)
し、直流電源に電源ケーブルを介して接続される
陽極および陰極並びに前記直流電源とは電気的に
接続されない放射能で汚染された被処理金属が前
記電解液中に浸漬される電解槽と、この電解槽内
の電解液中に設けられ、前記電解液を撹拌する撹
拌機構と、前記電解槽に連接され前記電解液中の
不純物を回収除去するフイルタと、前記電解槽内
に発生した硝酸蒸気および水蒸気を回収し水素ガ
スおよび酸素ガスを排気する排ガス処理装置とを
具備することを特徴とする放射能で汚染された金
属の除染装置。 ２ 前記排ガス処理装置はコンデンサ、デミスタ
および排気ブロアから構成されていることを特徴
とする特許請求の範囲第１項記載の放射能で汚染
された金属の除染装置。 ３ Ce3+−Ce4+−HNO3溶液系の電解液を収容
し、直流電源に電源ケーブルを介して接続される
陽極および陰極が前記電解液中に配設される電解
槽と、前記電解液を循環させる循環ラインにより
前記電解槽に連通され前記電解液を貯溜して放射
能で汚染された被処理金属が液中に浸漬される除
染槽と、前記電解槽および除染槽内の少なくとも
一方の電解液を撹拌する撹拌機構と、前記電解槽
および除染槽の少なくとも一方に連接され前記電
解液中の不純物を回収除去するフイルタと、前記
電解槽および除染槽内に発生した硝酸蒸気および
水蒸気を回収し水素ガスおよび酸素ガスを排気す
る排ガス処理装置とを具備することを特徴とする
放射能で汚染された金属の除染装置。 ４ 前記排ガス処理装置はコンデンサ、デミスタ
および排気ブロアから構成されていることを特徴
とする特許請求の範囲第３項記載の放射能で汚染
された金属の除染装置。[Claims] 1 An anode and a cathode containing an electrolyte of Ce 3+ −Ce 4+ −HNO 3 solution system and connected to a DC power source via a power cable, and electrically connected to the DC power source. an electrolytic cell in which a metal to be treated contaminated with radioactivity is immersed in the electrolytic solution; a stirring mechanism provided in the electrolytic solution in the electrolytic cell and stirring the electrolytic solution; and a stirring mechanism connected to the electrolytic cell. a filter that collects and removes impurities in the electrolytic solution; and an exhaust gas treatment device that collects nitric acid vapor and water vapor generated in the electrolytic cell and exhausts hydrogen gas and oxygen gas. Decontamination equipment for metals contaminated with 2. The decontamination device for metals contaminated with radioactivity according to claim 1, wherein the exhaust gas treatment device is comprised of a condenser, a demister, and an exhaust blower. 3. An electrolytic cell containing an electrolytic solution of Ce 3+ −Ce 4+ −HNO 3 solution, and an anode and a cathode connected to a DC power source via a power cable are disposed in the electrolytic solution, and a decontamination tank that is connected to the electrolytic tank through a circulation line that circulates the liquid, stores the electrolytic solution, and immerses the radioactively contaminated metal to be treated in the liquid; a stirring mechanism that stirs at least one of the electrolytic solutions; a filter connected to at least one of the electrolytic tank and the decontamination tank that collects and removes impurities in the electrolytic solution; and nitric acid generated in the electrolytic tank and the decontamination tank. 1. A decontamination device for metals contaminated with radioactivity, comprising an exhaust gas treatment device that recovers steam and water vapor and exhausts hydrogen gas and oxygen gas. 4. The decontamination device for metals contaminated with radioactivity according to claim 3, wherein the exhaust gas treatment device is comprised of a condenser, a demister, and an exhaust blower.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59106083A JPS60249097A (en) | 1984-05-25 | 1984-05-25 | Decontamination device for radioactive contaminated metal |
| FR858502984A FR2565021B1 (en) | 1984-05-25 | 1985-02-28 | APPARATUS FOR DECONTAMINATION OF RADIOACTIVE METAL WASTE |
| DE3507334A DE3507334C2 (en) | 1984-05-25 | 1985-03-01 | Device for disinfecting or decontaminating radioactively contaminated metallic objects |
| US06/710,178 US4663085A (en) | 1984-05-25 | 1985-03-11 | Apparatus for decontamination of radiation contaminated metallic waste |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59106083A JPS60249097A (en) | 1984-05-25 | 1984-05-25 | Decontamination device for radioactive contaminated metal |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60249097A JPS60249097A (en) | 1985-12-09 |
| JPH0574799B2 true JPH0574799B2 (en) | 1993-10-19 |
Family
ID=14424666
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59106083A Granted JPS60249097A (en) | 1984-05-25 | 1984-05-25 | Decontamination device for radioactive contaminated metal |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60249097A (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5452297A (en) * | 1977-09-08 | 1979-04-24 | Gen Electric | Method and device for recovering nuclear fuel |
| JPS5914000A (en) * | 1982-07-14 | 1984-01-24 | 神鋼フアウドラ−株式会社 | Method of removing radioactive material in electrolyte in electrolytic decontamination |
-
1984
- 1984-05-25 JP JP59106083A patent/JPS60249097A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5452297A (en) * | 1977-09-08 | 1979-04-24 | Gen Electric | Method and device for recovering nuclear fuel |
| JPS5914000A (en) * | 1982-07-14 | 1984-01-24 | 神鋼フアウドラ−株式会社 | Method of removing radioactive material in electrolyte in electrolytic decontamination |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS60249097A (en) | 1985-12-09 |
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